Java HttpServletResponse

HttpServletResponse is an interface from package javax.servlet.http. It extends javax.servlet.ServletResponse.

The important interface members are:
* addCookie(Cookie cookie);
* addHeader(String name, String value);
* sendError(int sc) Sends an error response to the client using the specified status code and clearing the buffer;
* sendError(int sc, String msg) Sends an error response to the client using the specified status.
* sendRedirect( String newLocation ) throws IOException - Sends a temporary redirect response to the client using the specified redirect location URL. Realised by http code 302 (Redirect).
* setHeader(String name, String value);
* setStatus(int sc) Sets the status code for this response.

Noticable methods from the super interface javax.servlet.ServletResponse:
* String getCharacterEncoding();
* String getContentType() - Returns the content type used for the MIME body;
* boolean isCommitted();
* setCharacterEncoding(String charset);
* setContentType(String type);

Java ServletContext

ServletContext is an interface from package javax.servlet;

Getting ServletContext
ServletContext could be get by session.getServletContext() method.
HttpSession could be get by request.getSession( boolean create );

The most important members are:
* addFilter(java.lang.String filterName, Filter filter) - Registers the given filter instance with this ServletContext under the given filterName;
* addListener(java.lang.Class listenerClass) - Adds a listener of the given class type to this ServletContext;
* Object getAttribute(java.lang.String name);
* ClassLoader getClassLoader();
* String getContextPath();
* getMimeType(java.lang.String file);
* log( String message, Throwable throwable );
* setAttribute( String name, java.lang.Object object );

Java HttpSession

HttpSession is interface from package javax.servlet.http.

Getting HttpSession
A HttpSession object could be get by request.getSession( boolean create );

The most important methods are:
* Object getAttribute(java.lang.String name);
* Enumeration getAttributeNames();
* long getCreationTime();
* long getLastAccessedTime();
* ServletContext getServletContext();
* invalidate();
* removeAttribute(java.lang.String name);
* setAttribute( String name, Object value );
* setMaxInactiveInterval(int interval) - Specifies the time, in seconds;
*

java HttpRequest

The interface HttpRequest is located in package javax.servlet.http.

Here are some important members:
* Cookie[] getCookies()
* String getHeader(java.lang.String name) - Returns the value of the specified request header as a String
* String getMethod() - GET, POST, or PUT
* String getQueryString() - Returns the query string that is contained in the request URL after the path.
* String getRemoteUser() - Returns the login of the user making this request, if the user has been authenticated;
* String getRequestURI() - Returns the part of this request's URL from the protocol name up to the query string;
* StringBuffer getRequestURL() - Reconstructs the URL the client used to make the request;
* HttpSession getSession( boolean create );
* boolean isUserInRole( String role );

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And some inherited from javax.servlet.http.Request:
* Object getAttribute( String name );
* Enumeration getAttributeNames();
* String getContentType() - Returns the MIME type of the body of the request;
* String getParameter( String name );
* Enumeration getParameterNames();
* String getServerName();
* int getServerPort();
* String getRemoteHost() - Returns the fully qualified name of the client ( or the last proxy that sent the request);
* setAttribute( String name, Object o);
* removeAttribute(java.lang.String name);
* Locale getLocale();